The present invention relates to a vacuum cleaner, and particularly to a vacuum cleaner of exhaust circumfluently flowing (circulation) type for making air exhausted from a motor fan incorporated in a vacuum cleaner main body circumfluently flow into, for instance, a suction nozzle for floors through a hose and a pipe.
In a general vacuum cleaner of floor moving type, air exhausted from a motor fan incorporated in a vacuum cleaner main body is entirely exhausted to the exterior through an exhaust outlet which is formed, for instance, at a rear surface side of the main body.
That is, dust which is sucked with air through a suction nozzle for floors is taken into the vacuum cleaner main body via a pipe and a hose, and air which has been removed of dust through a paper package or the like and used for cooling a motor of the motor fan is exhausted to the exterior through the exhaust outlet thereafter. At this time, since all of the exhaust air from the motor fan is exhausted, air is blown out to the exterior at a remarkable speed. Therefore, there is presented a drawback that dust deposited on a floor surface or on a carpet is whirled up through this exhaust air to be dispersed all over the room.
As disclosed in Japanese Examined Utility Model Publication No. 36553/11964 or in Japanese Unexamined Patent Publication No. 135795/11997, there are known vacuum cleaners which are provided for the purpose of reducing exhaust air blown out to the exterior in this manner or of improving dust-collecting effects wherein hoses, pipes and suction nozzle which are connected to vacuum cleaner main bodies are formed with suction air passages as well as exhaust air passages for making a part of or the entire air exhausted from motor fans circumfluently flow.
In such vacuum cleaners, hoses as well as pipes are arranged to be of concentric circular double structures wherein suction air passages are formed at inner sides while exhaust air passages are formed at outer sides.
However, in such vacuum cleaners of exhaust circumfluently flowing type, drawbacks are presented due to the arrangement of the concentric circular double structure of the pipe as well as the necessity of utilizing interstitial materials for maintaining outer and inner pipes in concentric circular conditions, so that excessive weight and thickness lead to inferior operatability and difficulty in practical use.
While there might be considered to separate an interior of a general pipe used for suction of air only by means of a plate-like partition to form an suction air passage and an exhaust air passage, the suction air passage will accordingly assume a semicircular section so that dust is more likely to be plugged when compared to general passages of circular shapes.
Further, while exhaust air is made to pass through an outer passage of the double structure in the arrangement of the prior art, air which is exhausted from the motor fan is heated by cooling the motor so that in case such an exhaust air passes through the outer exhaust air passage of the double structured pipe, an outer surface temperature of the pipe will be increased to result in drawbacks in view of usage.
Moreover, the hose needs to be of a double structure type in such exhaust circumfluently flowing type vacuum cleaners. However, in vacuum cleaners, there are generally employed hoses which are called one-layer and two-wiring hoses and are relatively heavy hoses incorporating therein coil wiring exhibiting conductive (so that they can be used as signal wiring) and shape-retaining characteristics. Therefore, in case of employing a double structure with such a hose, the weight of the entire hose will become excessive and results in inferior operatability and difficulty in practical use.
Further, while connecting pipes for attaching a hose to a hose-inserting inlet of the vacuum cleaner main body and a hose grip portion are attached to both ends of the hose, a hose, like an one-layer and two-wiring hose, which incorporates therein coil wiring needs to be attached and fixed to an hose-installing end of the connecting pipe in a screwing manner, and performing this operation at both ends of the double structured hose twice each, that is, four times, is quite troublesome. Further, attaching and fixing needs to be performed while taking torsions in the hose into consideration. Thus, assembling processes of the hose become quite complicated.
Moreover, deformations might sometimes remain in hoses incorporating therein coil wiring such as one-layer and two-wiring hoses when erroneously treading thereon. In case only the inner hose is deformed in a double structure hose, such a deformation cannot be recognized from its external appearance, and the plugging of dust is apt to happen.
The present invention has been made for solving such problems, and it is an object of a first invention to achieve for a light-weighted and slim-sized pipe of an exhaust circumfluently flowing type vacuum cleaner through which a suction air passage and an exhaust air passage extend.
It is an object thereof to restrict increases in temperature on an outer surface of the pipe owing to heat of exhaust air.
It is an object of a second invention to achieve for a light-weighted double structure hose of an exhaust circumfluently flowing type vacuum cleaner through which a suction air passage and an exhaust air passage extend.
It is an object thereof to simplify assembling processes of the hose and to make deformations of an inner hose visible from its external appearance.